1. Field of the Invention
This invention relates to an image vibration reduction apparatus best suited as a hard vibration reduction apparatus for a camera.
2. Related Background Art
In an image vibration reduction apparatus of this kind according to the prior art, a lock mechanism for locking an image vibration reduction optical system has not generally been used. Also, even an image vibration reduction apparatus having a lock mechanism, design has been made such that an image vibration reduction optical system is moved to the central portion and then is locked.
However, when the image vibration reduction optical system is to be protected from vibration, or when the image vibration reduction optical system is moved under the influence of noise or the like and causes image vibration, it is preferable to lock the image vibration reduction optical system. Further, as the lock mechanism, it is preferable that the image vibration reduction optical system need not be moved to the central portion and can be locked at whatever position it may be.
There is known a vibration reduction apparatus in which vibration created in a camera, a video camera or the like is detected by an angle-velocity sensor or the like and a vibration reduction optical system which is a portion of a photo-taking optical system is moved in a direction opposite to the direction of the detected vibration and the optical axis thereof is varied to thereby reduce image vibration. To effect such vibration reduction, it is necessary to know the fiducial position (origin) of the vibration reduction optical system. This fiducial position is memorized in advance in a memory portion such as a ROM.
However, the aforedescribed vibration reduction apparatus according to the prior art has suffered from the following problems.
In the setting of the fiducial position of the vibration reduction optical system, the characteristic of a position detecting sensor is varied by environment (such as temperature and humidity), and this has led to the problem that when vibration reduction is effected on the basis of the preset fiducial position, an error occurs.
To solve this problem, there is known a method of actually mounting a temperature detection circuit or the like in the apparatus and changing the fiducial position in conformity with temperature. In this method, however, a discrete circuit such as the temperature detection circuit becomes necessary, and this leads to the problem that the apparatus becomes bulky and costly.
There is also the problem that if the fiducial position of the vibration reduction optical system cannot be detected accurately, highly accurate vibration reduction cannot be effected.